Pomander of Steel will cut down what the attack does--it's like 2k base damage, and Steel cuts that down a lot. You should also get a ton of potions in PotD and the cooldowns are fairly short--those things are lifesavers and if I do a PotD run I usually bind them to a hotbar somewhere. But yeah, the AOE hits semi-hard and taking that hit + an add cast while you're stunned will usually be death, and healing up in between is important.
PC but I'm on controller so UI is the same. The PotD Pomander inventory highjacks your character window, so hit start and pick Character from the list to bring the PotD window back up.
